New beautiful results on marine particle speciation, a challenge for the GEOTRACES community…

Advanced Light Source x-ray spectromicroscopy (XANES) allows a fine description of the marine Fe pool chemical speciation and mineralogy. This work describes diverse arrays of iron particles (20- 700 nm), showing impressive variations in the oxidation state and composition of these iron particles between the coasts of South Africa and Antarctica. Moreover, different iron pools are occurring in different frontal zones. Because particle speciation is directly linked to the element solubilities, these differences may affect the production of bioavailable dissolved iron.

Iron_particle_speciation

Source : Science (click on the image to view it larger)

Reference:

B. P. von der Heyden, A. N. Roychoudhury, T. N. Mtshali1, T. Tyliszczak, S. C. B. Myneni. (2012). Chemically and Geographically Distinct Solid-Phase Iron Pools in the Southern Ocean: Science 338 (6111): 1199-1201, DOI: 10.1126/science.1227504

Latest highlights

The development of the modern Antarctic Circumpolar Current occurred much later than previously thought!

This study is challenging the belief that the onset of the Antarctic Circumpolar Current was solely triggered by the opening and deepening of Southern Ocean Gateways.

A dynamic iron cycle in Peru

Gu and colleagues explore the temporal variation of iron over 11 cruises along the Peruvian shelf.

Trace metal fluxes of cadmium, copper, lead and zinc from the Congo River into the South Atlantic Ocean are supplemented by atmospheric inputs

Liu and colleagues show that rainfall augments some fluxes of trace metals from the Congo River.

Aluminium, manganese, iron, cobalt, and lead display contrasting fate along north–south and east–west sections in the North Pacific Ocean

Chan et co-authors provide a comprehensive view of trace metal distribution in the subarctic Pacific Ocean.

Rechercher